ABSTRACT
The multi-decade creep and shrinkage prediction for modern high-performance concretes poses a significant challenge. Here we present Model B4, the improved and extended successor of the 1995 RILEM recommendation Model B3. We demonstrate its strength by comparing it statistically to a wide set of previous models, such as Model B3, the fib Model Code Models 90/99 and 2010, the 1992 ACI 209 Model, and the Gardner-Lockman Model 2000. The calibration of Model B4 is based on a new laboratory database, developed at Northwestern University, and additionally on multi-decade deflections of 69 large-span prestressed bridges. The multi-decade creep behavior is updated using a joint optimization of the laboratory and bridge deflection databases. Two sets of equations to predict the parameters of the creep and shrinkage model, one utilizing solely strength, and one based on composition information, have been calibrated. They include the effects of admixtures, aggregates, and cement type.
